Titanium base alloys



United States Patent TITANIUM BASE. ALLOYS Milton B. Vordahl, Beaver, Pa., assignor, by mesne as.- signments, to Crucible Steel Company of America, Flemington, NJ., a corporation of New Jersey No Drawing. Application December 13', 1957' Serial No. 702,533

2 Claims. (Cl. 75-1755) cations Serial, No. 131,044, filed, December 3, 1949, now

Patent No. 2,675,309, dated April, 13, 19.54, and Serial No. 385,720, filed October 12, 1953, now abandoned.

The alloys of the invention may contain from about 0.5 to 40% aluminum together with about 0.5 to manganese. Where the manganese content is on the high side of its. range, the aluminum content is preferably on the low side of its range, and vice versa, for the best combination of properties.

The alloys containing about 0.5 to 13% aluminum and about 0.5 to 13% manganese, are characterized by high. tensile strength combined with adequate ductility for fabrication purposes, i.e., forging, extruding, rolling, drawing, etc., provided the manganese content is on the high side of its range when the aluminum content is on; the low side of its range and vice versa.

The alloys containing aluminum and/or manganese contents above about 13%, tend to become increasingly brittle with increase in total alloy content, but are usablein cast form, being characterized in general by high. hardness.

As is known, pure titanium, metal" has at: normal; or atmospheric temperatures a close-packed hexagonal or all-alpha microstructure which transforms at about 885 C. and above to a body-centered cubic or all-beta microstructure. Aluminum alloyed with titanium tends to stabilize the alpha phase, whereas manganese tends to promote retention and stabilization of the beta phase at; normal or atmospheric temperatures. The alloys of; the invention are accordingly characterized in general by a, mixed alpha-beta microstructure at room temperature, which may contain in addition, eutect-oid decompositionproducts depending on the heat treatment, since manganese is a beta-promoter of the sluggishly reactive eutectoicl; type.

In my patent aforesaid I have described ternary titanium-aluminum-manganese alloys containing about 1, to 7% each of aluminum and manganese, which are strong and ductile. My further investigations have established,

ice

as shown in my copending application Serial No. 385,:

obtained over the range of from more than 7% up to about 13% aluminum with about 0.5 to 13% manganese and also over the range of more than 7% manganese with about 0.5 to 13% aluminum.

I, have further discovered, also as shown in my application, Serial No. 385,720 aforesaid, thattitaniumaluminumfmanganese base alloys containing about 0.5 to 13% each of aluminum and manganese may be further strengthened with retention of adequate ductility for fabrication by additions of beta promoters other than manganese, such as Mo, V, Cb, Ta, Zr, Cr, W, Fe, Co, Ni, Cu, Be and Si. The beta promoters Mo, V, Cb, Ta and Zr are beta-isomorphous with titanium andhence may be added to the base Ti Al-Mn alloy in large amounts ranging up to-40 or 50% with increasing; efiect on room temperature beta stabilization. The sameis true to a lesser degree of the sluggishly eutectoid beta promoters Cr, Fe and W, with respect to which chromium and tungsten are effective up to about 20% for either or both, while iron is effective up to about 7% without unduly embrittlingthe resulting alloy. Cobalt, nickel and copper transform more or less rapidly into eutectoid decomposition products; which tend to produce embrittlement, and hence are subject to lower tolerances, i. e., up to about 5% each or in aggregate. The lower elfective limit for these additions is about 0.5% for all except Ni, Co, Cu, the lower efiective limit for the latter being about 0.25% The upper effective limit for Si and Be to avoid undue embrittlement is about 2-3% and the lower effective limit about 0.1%

The alloys of this invention are susceptible to embrittlement by an excess of carbon, oxygen and/ or nitrogen. While the quantities of carbon, oxygen and nitrogen normally present in high quality commercial titanium can be tolerated, the oxygen and nitrogen content should not exceed about 0.1% each andv the carbon content should not exceed about.0.3%.

Mechanical properties of ternary Ti-Al-Mn alloysaccording to the invention are given below in Table, I. In producing the alloys of Table I, titanium metal of high purity, i.e., iodide base was employed.

It will. be seen from the test results of Table I that alloys of high strength combined. with. adequate ductility for purposes of fabrication are obtainable over the range extending up to about 13% each of aluminum and manganese, provided that for a high content of one of these elements, the other should be present in correspondingly lower amount.

As regards requisite ductility for'fabrication purposes,

TABLE '1 Mechanical properties of Ti-Al-Mn titanium base) alloys (iodide Composition, Percent Tensile Properties, (Balance Titanium) p.s.i. 1,000 Percent Elongation in 1!! Condition 1 0.2% Ofiset Yield A1 Mn 0, O, N Ultimate Percent Reduction in Area MBR, T, L 9

acacia cu m couaaooooom m mmUlUlUl 999999 comm ena-

eeeeeeee oppppoo Ewwwwwwwwwwwwwwww 90 ocql l R=rolled; A=annealed; Q=quenehed; numerals represent temperature in "0.; AC=as cast.

I Minlmum bend radius, longitudinal.

Table II below gives mechanical properties showing the effect of adding the various other beta promoters to the Ti-Al-Mn base alloy of the invention. As noted in 35 the table, the majority of the analyses were derived from titanium metal of commercial purity as obtained by the magnesium reduction of titanium tetrachloride, one example being derived from iodide titanium base metal, as indicated.

It will be seen that the quaternary and higher component alloys of Table II, containing at least one beta promoter "in addition'to manganese are in general characterized by high tensile strengths and excellent bend ductilities'. i y

' The alloys of the invention may be made by melt casting in a'cold mold furnace employing an arc electrode in an inert atmosphere or by equivalent procedures.

TABLE II Mechanical properlres of Tl-Al-Mn alloys plus other beta additions Composition, Percent Tensile Properties, MBR, T 1

(Balance Titanium) p.s.i.X1,000 Percent Percent Elonga- Reduc- 1 4 Condition 1 tion tion in VHN 0.2% Ultimate in 1" Area Al Mn Other Oflset Strength L '1 Yield (Commercial Purity Ti-Base) A... R and A 850.-. 48 71 21 61 187 0. 8 0. 8

R and A 850 88 101 19 48 304 1. 7 2. 6 R 650, A 650 115 v 136 280 3.0

4 2. 5 R 760, A 700"..- 131 145 12 34 331 2. 9 5, 3 2 3 R 760, A 600.-.-- 127 152 10 31 333 3. 2 '4; 2 4 4 R 800, A 700... 143 164 6 329 1. 0 6.3 4 2. 6 R 760, A 700..-" 130 3 9 332 .7. 8 9 4 2 5 R 760, A 700- 126 129 8 36 353 2. 6 5. 8 4 2. 5 R 760, A 700.-." 5 33 I, 355 2.8 8. 1 4 2. 5 R 760. A 700.-.... 139 146 13 38 362 2. 5 5. 7 4 2. 6 R 760, A 700...-.. 117 138 12 29 348 1. 9 9 4 2. 5 R 760, A 700. 144 148 7 38 355 2. 5 5. 9 2 3 R 760, A 600 128 142 14 37 330 1. 5 4. 7 4 2. 5 R 760, A 700. 138 144 6 33 35B 148 8 4 4 R 800, A 700.-.-.. 138 142 11 38 319 0 0 2 2 R 760, A 800.-." 137 146 9 25 329 1. 2 v 4.4 4 2. 5 R 760, A 700.. 143 151 11 31 286 2. 6 9 4 4 R 700 154 6 24 361 0.9 6

(Iodide Ti-Base) I I v "Minimum bend radius-longitudinal and transverse.

What is claimed is:

1. A titanium base alloy consisting essentially of about: 0.5 to 13% each of aluminum and manganese and at least one beta promoter selected from the group consisting of 0.5 to 40% of molybdenum, vanadium, columbium, tantalum and zirconium, 0.5 to 20% of chromium and tungsten, 0.5 to 7% iron, 0.5 to 5% of cobalt, nickel and copper, and 0.1 to 3% of silicon and beryllium, characterized in having a tensile strength of at least 100,000 psi. and a minimum bend radius of at least 201.

2. A titanium base alloy consisting essentially of about: 0.5 to 13% each of aluminum and manganese, the manganese being present on the high side of its range when aluminum is present on the low side of its range and vice versa, said alloy also containing at least one beta promoter selected from the group consisting of 0.5 to 40% of molybdenum, vanadium, columbium, tantalum and zirconium, 0.5 to 20% of chromium and tungsten, 0.5 to 5% iron, 0.5 to 5% of cobalt, nickel and copper, and 0.1 to 3% of silicon and beryllium, characterized in having a tensile strength of at least 100,000 p.s.i. and a minimum bend radius of at least 20T.

6 References Cited in the file of this patent UNITED STATES PATENTS 2,139,516 Norris Dec. 6, 193s 2,464,836 Thomas Mar. 22, 1949 2,622,023 Frazier Dec. 16, 1952 2,675,309 Vordahl Apr. 13, 1954 2,798,806 Jaifee July 9, 1957 2,810,643 Methe Oct. 22, 1957 FOREIGN PATENTS 718,822 Germany Mar. 24, 1942 OTHER REFERENCES 

1. A TITANIUM BASE ALLOY CONSISTING ESSENTIALLY OF ABOUT: 0.5 TO 13% EACH OF ALUMINUM AND MANGANESES AND AT LEAST ONE BETA PROMOTER SELECTED FROM THE GROUP CONSISTING OF 0.5 TO 40% OF MOLYBDENUM, VANADIUM, COLUMBIUM TANTALUM AND ZIRCONIUM, 0.5 TO 20% OF CHROMIUM AND TUNGSTEN, 0.5 TO 7% IRON, 0.5 TO 5% OF COBALT, NICKLE AND COPPER, AND 0.1 TO 3% OF SILICON AND BERYLLIUM, CHARACTERIZED IN HAVING A TENSILE STRENGHT OF AT LEAST 100,000 P.S.I., AND A MINIMUM BEND RADIUS OF AT LEAST 20T. 